1. Technical Field
The present disclosure relates to turbo machines.
2. Description of the Related Art
Various bearing structures have been developed for turbo machines.
As illustrated in FIG. 11, for example, Japanese Unexamined Patent Application Publication No. 2011-149390 discloses a supercharger including a turbine shaft 31, a bearing housing 30, a bearing 62, a bearing 63, a bearing retainer 61, and a bearing holder 64. The supercharger is a turbo machine. The bearings 62 and 63 rotatably support the turbine shaft 31. The bearing retainer 61 is disposed in the bearing housing 30 and has a hole 71 in which the bearings 62 and 63 are disposed. The bearing holder 64 includes a bearing confronting portion 86. The bearing confronting portion 86 is positioned outside the bearing retainer 61 and faces an axial end 82 of the bearing 63. A confronting surface 85 of the bearing holder 64, which faces the bearing retainer 61, is in contact with a rear end of the bearing retainer 61. In addition, the axial end 82 of the bearing 63 is positioned at the same position with the rear end of the bearing retainer 61 in the front-rear direction. Thus, the axial end 82 of the bearing 63 is in contact with the bearing holder 64.
The bearing 63 is positioned close to the end of the hole 71 in the bearing retainer 61 compared with bearings of conventional turbo machines. This configuration allows adjacent bearings to be spaced at larger intervals, leading to an improvement in vibration damping characteristics, and as a result, provides high rotation stability.